Projectile



Jan. '17, 1928.

H. J. NICHOLS PROJECTILE Original Filed Feb. 10. 1923 Patented Jan. 17,1928.

UNTED STATES.

ATENT OFFICE.

PROJECTILE.

Application filed February 10, 1923, Serial No. 618,339. Renewed April2, 1927.

This invention relates to projectiles, and particularly to projectilesof the armorpiercing type.

Armor-piercing projectiles heretofore employed have been furnished withbase-plugs formed from a solid block of steel of massive proportions,which plugs have been securely screwed into the rear of the projectilebody. The main purpose of this form of plug has been to constrain gasesgenerated by the explosion of a charge of explosives contained within acavity in the projectile in such a manner that the walls of theprojectile are subjected to the full expansive force of the explosivegases and are thereby disrupted into numerous fragments. The effectsought is technically known as complete fragmentation.

The above type.v of base-plug gave satisfactory results for many years,but as a .result of the increase in the range of modern gun fire aprojectile is required to effect perforation of armor under newconditions. The line of fire at long ranges is not perpendicular ornormal to the face of vertical armor, but is considerably inclinedthereto. This change in the direction at which the projectile encountersthe armor has caused the projectile to be subjected to powerful sidestresses, as well as increased longitudinal stresses, resulting infailure of the pro ectiles to penetrate and their destruction on theface of the armor.

In order to increase the ability of projectiles to withstand sidestresses and to secure what is technically known as penetration atoblique impact, it has heretofore been proposed to chamfer or taper theprojectile body from the vicinity of the rotating band rearwardly to thebase, thread this conical portion,-and attach thereto a band of metal,cylindrical on the outside diameter and tapered inside, to fit theconical portion of the projectile body. When a projectile thusconstructed strikes itsobjective obliquely, the interiorly tapered bandis torn loose, thereby permitting the reduced portion of the projectileto enter the hole in the plate more readily. This construction, whilepartially accomplishing its purpose, is expensive, limited inapplication, and weakens the pro- Tectile at the base which isdetrimental to complete fragmentation.

An object of this invention is to provide a ness of the explosivechamber notwithstanding deformation of the rear portion of theprojectile body, thus preserving the frag menting qualities of theprojectile.

The invention will be readily understood by reference to theaccompanying drawings, illustrating several embodiments of the inventiveidea, in which- Fig. 1 is a longitudinal sectional view of a projectileembodying the present invention;

Fig. 2 is a detail sectional view of one form of base-plug which may beemployed in my improved projectile;

Fig. 3 is a similar view of another form of base-plug which may beemployed;

Fig. 4 is a diagrammatic view illustrating the conditions which existwhen a projectile strikes armor plate at angles less than from thenormal;

Fig. 5 is a diagrammatic view illustrating the action ofa projectilewhen striking at angles greater than from the normal; and

Fig. 6 is a similar view illustrating one of the various conditionswhich exists when the projectile strikes at an angle betweenapproximately 45 and 60 from the normal.

Referring to the drawings, wherein like reference numerals indicate likeparts throughout the several views, 7 is the body portion of my improvedprojectile having searmor at oblique angles, it is necessary that thebase-plug, closing the rear end of cavity 10, so cooperate with thewalls of the shell as to overcome the tendency of the rear end of theshell to be crushed, sheared, or otherwise disrupted, owing to thelateral strains developed at the rear of the shell. To this end thebase-plug 11, in conformity with this invention, is so constructed as tobe flexible, and is secured to body 7 in any suitable manner as by meansof screw-threads 12.

Instead of being fiat or slightly concave, as in the usual construction,the inner face 13 of base-plug 11 is convex, and of a truncated conicalshape projecting slightly into explosive chamber 10. At the forward endof face 13, and formed concentrically therewith, is a threaded opening14 for receiving a fuse or exploder 15 of any suitable type.Fuse-opening 14 is widened at the rear to form an axial cavity 16. Itwill be understood that, while cavity 16 is shown as conical in shape,throughout a portion of its length,

- the same may be of any desired contour, its

- is usually provided between the body 7 purpose being to removematerial around the axis of plug 11 suiiicient to render the plugelastic and yielding to side stresses which deform, or tend to deform,the projectile when penetrating armor plate at oblique angles.

s illustrated in Fig. 1, the rear end of cavity 16 may be open.Preferably, however, said cavlty is closed as shown in Fig. 2 by adetachable plate 17 held in place by means of screws 18. If desired, agasket 19 may be fitted between plate 17 and plug 11 to prevent gasesfrom entering cavity 16 when the .proectile 1s fired from the gun. A.gasket 20 plug 11 and Cavity 16 may be filled with some yieldingmaterlal such as sand or aluminum which, by lts opposltion todeformation of the plug, Wlll asslst in maintaining a gas-tightconnection between as follows Referring first to Fig. 4, illustratingthe conditions which exist when the projectile strikes side armor at anangle less than 45 said plug and the body 7. As shown 1n Flg. 3, ayielding material 21.-

The section of the plate opposite the nose of the projectile is notsymmetrical with the line of fire and its reaction is inclined to saidline of fire, resulting in a transverse movement which tends to bringthe axis of the projectile perpendicular to the face of the plate. Theseconditions are further illustrated in Fig. 4 which also illustratestheprincipal force acting. This effect is known as side-whip of theprojectile. Its force tends to bend the projectile around the rim of thehole being punched in the armor plate. The projectile body yieldselastically under the/forces acting and continues to penetrate until thebase portion, containing the baseplu'g, attempts to enter the punchedhole. \Vhen the base-plug is formed of a solid block of steel, it ispractically unyielding and, at this polnt, produces destructivecrossbreaking stresses which frequently break the rear end of theprojectile or greatly weaken the same. When my improved flexiblebaseplug is used, however, the plug yields in the same manner as theprojectile body, absorbs some of the forces acting on the rear end ofthe projectile and thereby assists in holding the projectile intact andin accomplishing perforation of the plate.

When the projectile strikes at more than from the normal, this usuallybeing the case where the projectile encounters horizontal or deck armor,the result is as indicated in Fig. 5. The projectile strikes the platewith the side of its ogive and does not penetrate immediately but bendsthe .armor inwardly. This action, as in the previous case, tends toretard the motion of the for ward part of the projectile, therebycausing a transverse movement of the longitudinal axis. This movementis, however, away rather than toward the normal, i. e., there isa'tendency of the shell to glance. The result is that the rear of theprojectile is forced sidewise and it smashes with great force againstthe face of the armor. The rear portion of the body, if fitted with asolid base-plug, cannot yield elastically and is crushed as if byaforging hammer. When the projectile is provided with my flexiblebase-plug, however, the base yields elastically to the' forces actingand thereby absorbs a large part of these forces and diminishes thecrushing force acting on the projectile body,'thus lnsuring that theprojectile will be preserved intact.

When the projectile strikes at an les between approximately 45 and 60, te pros jectile may penetrate or may strike a glancing blow and rebound.One of the possible conditions is that illustrated in Fig. 6, whereinthe point of the projectile may not at first bite or penetrate, but asthe plate, if thin, is deformed, the bending of the plate increases theangle between the face of the plate and the longitudinal axis of theprojectile, causing the projectile to bite. There is, however, asimultaneous tendency for the projectiles longitudinal axis to bedeflected toward parallelism with the plate and for the projectile toglance. The effect of these influences cannot be predicted, but it willbe seen that the desirability of a flexible base-plug is-substantiallyas great as in the cases previously illustrated.

If my improved projectile and base-plug be deformed, due to the actionof forces described above, they will be deformed elastically and in thesame degree, and the connection between the base-plug and the body willbe preserved. Therefore, as long as a projectile remains intact, thegeneration of a pressure inside of the projectile cavity will expandobturating lip 24 into engagement with the projectile body, sealing theexplosive chamber so that the full expansive force of the explosivegases may be exerted against the walls of the projectile and the face ofthe base-plug. The pressure of the gases on the inner face 13 and theresistance of screw-threads 12 react in such a manner asto expand theperimeter of plug 11, therebyinsuring against the escape of the gasrearwardly past said plug and insuring complete fragmentation of theprojectile.

Itwill be perceived that I have provided a projectile of superiorability as regards penetration of armor plate at oblique impact and atthe same time have provided a projectile'which will meet the mostexacting requirements as to fragmentation.

It will be noted that, while my improved pro ectile comprises abase-plug which, y1elds to side stresses, such as have been described,the form and construction of said plug is such that its ability towithstand the longitudinal stresses generated by the explosion of thefragmenting charge is fully the equal of, if not superior to, the solidplugs heretofore used.

While several embodiments of the inventive idea have been heretoforedescribed and illustrated in detail, it is to be understood that theinvention is not limited thereto, and that the inventive idea maybeembodied in various mechanical expressions within the limits of theappended claims.

\Vhat is claimed is 1. A projectile comprising a body portion having acavity therein, and flexible means for closing said cavity for rigidlyresisting longltudinal stresses, and for yieldingly resisting the radialstresses encountered when the projectile penetrates its objective.

2. An armor-piercing projectile comprising a body portion having acavity therein and a flexible plug for closing said cavity.

3. A projectile comprising, in combination with a body portion, aflexible base plug having an inner face of truncated conical shape, saidplug being adapted to rigidly resist longitudinal stresses and toyi'eldingly resist the radial stresses developed when the projectilepenetrates or strikes its objective at an oblique angle.

4. A projectile comprising, in combination with a body portion, a baseplug having an annular obturating groove in the front face thereof andadapted to rigidly resist lon itudinal stresses and to yieldingly resistt e radial stresses developed when said projectile penetrates or strikesits objective at an oblique angle.

5. A projectile comprising, in combination with a body portion, a baseplug having a concentric opening therein, the forward portion of saidopening being of relatively small diameter, and the after portionthereof being of relatively large diameter, said plug being so formed asto rigidly resist longitudinal stresses and yielding resist radialstresses en-. countered when the projectile strikes its objective.

6. An arn'ior-piercing projectile comprising, in combination with a bodyportion having a cavity for explosives therein, flexible means forinsuring fragmentation-when the projectile penetrates at oblique angles.

7. An armor-piercing projectile comprising, in combination with a bodyportion hav ing a cavity for explosives therein, a flexible base-plugfor increasing penetration when the projectile strikes its objective atan oblique angle.

8. A flexible base-plug for armor-piercing projectiles, having anobturating groove in the front face thereof, said face being oftruncated conical shape and extending beyond the front periphery of saidplug.

9. Flexible means for sealing the rear end of the explosive cavity of anarmor-piercing projectile and adapted to maintain said seal during thepassage of said projectile through armor-plate at oblique angles.

10. A deformable base-plug for a projectile having the periphery thereofthreaded,

an axial cavity of varying diameters extending therethrough, and aforward face of truncated conical shape projecting beyond the forwardend of said threaded portion.

11. Aprojectile comprising, in combination with the body portion, abase-plug recessed at its axis to render the same elastic.

12. A projectile comprising, in combination with the. body portion, adeformable base-plug adapted to yield to lateral stresses, rigidlyresist longitudinal stresses and maintain a gas-tight seal'with saidbody portion when the projectile strikes its objective.

13. A deformable base-plug for an armorpiercing projectile adapted toconform to the deformations of the' body portion of said projectileduring the piercing of an objective by said projectile. V

14. A deformable base plug for an armorpiercingprojectile adapted toyield to lateral IOU - base-plug ada ted to cooperate with said body inyiel ing elastically to the side stresses set up in said body portionwhen the projectile strlkes its objective at an oblique, angle. 4

In testimony whereof I have signed this, specification.

HARRY J. NICHOLS.

